Carrier constructions for bulk fluids



1962 K. E. GARDNER ETAL 3,064,612

CARRIER CONSTRUCTIONS FOR BULK FLUIDS Filed Oct. 20, 1960 4 Sheets-Sheetl Nov. 20, 1962 K. E. GARDNER ETAL 3,064,612

CARRIER CONSTRUCTIONS FOR BULK FLUIDS Filed Oct. 20. 1960 4 Sheets-Sheet2 INVEN TOR. KA'A/A/ETH E. MED/YER 144 175? 1? GER/CM ALE EFT P VELTRE'Nov. 20, 1962 K. E. GARDNER ETAL 3,064,612

CARRIER CONSTRUCTIONS FOR BULK FLUIDS 4 Sheets-Sheet 3 Filed Oct. 20.1960 BY Azsikr 2 1 5025 Nov. 20; 1962 K. E. GARDNER ETAL CARRIERCONSTRUCTIONS FOR BULK FLUIDS 4 Sheets-Sheet 4 BY AME/5P7 .P 14-27795Filed Oct. 20. 1960 The present invention relates to vehicular carrierconstructions for bulk fluids and it comprises a continuationin-partapplication based upon patent application Serial No. 829,410, filed July24, 1959, and now abandoned. More especially, the invention relates tocarrier vessels such as-are used to transport hydro-carbon fuels and thelikein liquid form. Although the invention is defined with specificreference to transporting hydrocarbon fuels, it has like application totransporting other liquids which must ofnecessity be carried at:temperatures varying appreciablyabove and below the ambient of thecarrier structure;

Problems arising from the transportation of hydrocarbon fuels includeloss by evaporation. In normal transporaunless the gases of vaporizationare withdrawn and liquefied -by refrigeratioma notable loSs of cargooccurs. This construction will permit safe circulation-to these ends.

Safety of thevesselstructure, in the event of leakage and temperaturedrop, presents a situation that must also bemet. Accordingly, allspecifications mustmeet the recognized standards of the ClassificationSocieties such as the American Bureau of Shipping. This invention hastherefore been devised with provisions for liquefying the gases ofvaporization by refrigeration and returning the hydrocarbons in liquidform to the cargo tanks which are located within the hold of thecarrier. Particular attention is given to the provision of a secondarybarrier to contain the cargo upon leakage and in such massiveconstructions as ships, this, too presents practical and economicproblems which have been solved herein. Moreover, an effort is madehereby to utilize maximum hold space in confining the respective cargotanks without sacrifice of safety to the ship while at the same timecreating a lightweight and highly safe means for retaining the tanks,considering the motions imposed by variant seaway, weather conditions orcargo shifting.

It is an object of this invention to provide means for safely securing anumber of large fluid retaining cargo tanks within the holds of acarrier, whereby gaseous vapors of said tanks may be continuouslyliquefied by refrigeration and the liquid returned to the cargo tanks.

In the area of safety control, it is important that any leakage in thecargo tanks be adequately detected, confined and corrected withoutresort to the expense of removal of the tank. Therefore, a space isprovided between the boundary of the cargo tanks and the ships structureto permit ready inspection and subsequent repair to any of the tanks.Detection and repair in transit is thus an objective of the invention,as is control against excessive temperature drop to structural elementsof the carrier.

Yet another object of invention is to provide in carriers of the typedefined, cargo tank anchoring means whereby independent cargo tanks arepermitted multi-directional expansion and contraction in horizontal andvertical planes, all without rigid tank attachment to deck structure,the anchoring means being immovable with respect to the carrierstructure but yielding to movement of cargo tanktructure.

Still another objective of invention lies in providing unique means forsafely securing cargo tanks to vessel construction permitting expansionand contraction in re sponseto variation in the temperature above andbelow the ambient of the vessel.

Another object of' the invention is to provide unique weatherudeckaccessto each fiuid cargo tank, by flexible connection to the shipsstructure, allowing free movement of respective cargo tanks independentof any movement ofthe ships hull.

With these and other objects in view, the invention and allmodifications thereof will be more completely understood from referenceto the following drawings in which:

FIGURE 1 is an elevational or profile view of a typical carrier vesselenlarged to accommodate a grouping of independent cargo tanks inlongitudinal alignment;

FIGURE 2 is a View in vertical or midship section of the'carrier andhold of FIGURE 1;

FIGURE 3 is aschematic of the foundation assembly for one completecargo:tank containing at least two cargo cells;

FIGURE 4 is a fragmentary view in expanded perspective of a detail ofthe centerline foundation assembly shownschematically in FIGURE 3;

FIGURE 5 is a fragmentary view in expanded perspective'showing thedetail bolting for inboard support depicted schematically in FIGURE 4;

FIGURE 6 is an expanded view in fragment of a per tion of tankstabilizing assembly appearing atop the tank of FIGURES 2 and 3;

FZGURE7 is an expanded view in fragment of an outboard foundation memberappearing in support of the tankof- FIGURES 2 and 3;

FIGURE 8 is a fragmentary view in expanded perspective showing thedetail bolting for an outboard support depicted schematically in FlGURES2 and 3.

With specific reference to FIGURE 1, there is shown a shiplilo having adisplacement hull 1%, bridge H 4 and afterquarters or poophouse 1%. Theship has masts 1G8 and booms 168'. The particular construction shown isof a liquid hydrocarbon fuel (LPG) carrier wherein the relati vedisposition of cargo tanks to hull appears in fragment. The deck lfrii,as secured to the hull construction'1ii2, includes in its externalconfiguration, transverse structural beams 120, said beams being moreclearly depicted'with reference to FIGURE 2 at the top thereof. Thebeams-extend athwartships to the outer hull, those substantially alignedwith the false bulkhead being in supporting alignment with the uppertrailing extension thereof;

Theoverall hull ltiZincludes an inner or second barrier hull- 112. (FIG.2), spaced from the outer hull by reinforcement shown; the includedspace providing wing anddouble-bottom" tanksfor a liquid cargo otherthan the tank-contained principal hydrocarbon. F or example, certaingrades of'fuel oils may be carried in the wing tanks which would provideballast and also serve to insulate or reducetemperature drop: in thecarrier structure should leakagefromthe cargo tanks occur. Other safetyfactors include the fixed concrete ballast 116 on the bottom 114of-inner hull H2 and there is provision for Water spray within the cargoholdand between inner hull and cargo tank. The water spray system isadapted to bring, vapor heat to the area in which a leakage might occur,this area including not only thecargo hold between tank and inner. hullbut also topside and the refrigerating compressor'rooms;

In thisconstruction, six major cargo tanks are shown each havingconventional interior framing and each: being compartmented intoadjacent water tight cells and 140'. The hatches and appropriate pumpingstationsv serving each-of the cells of the respective major cargo tanks13% may be seen in FIGURE 2. Cargo tanks 3 are disposed in alignmentwith the keelson of the ship, in balanced relation thereto. A suitabletank sluice valve 144 is fitted at the lower extremity of bulkhead 142.Its operation is remote from the control above the weather deck 110.

The exterior of each cargo tank is insulated with consecutivethicknesses of mineral wool insulation 132 which is preferably JohnsManville BX-S or equivalent, covered by galvanized steel wire cloth #8mesh, and alternate coats of Foster fire-retardent mastic and plasticvapor barriers as recommended by the insulation manufacturer. Thisinsulation is to be attached to the cargo tank by means of Nelson weldedstuds, sealed in an approved manner. The bottom of the main deck 110, inthe tank hold areas between the longitudinal and transverse bulkheads,is also insulated with 1 of AP. 320 Fiberglass. As each cargo tank holdis made of nickelsteel, this provides a second barrier to insure safecontainment within the individual holds. These cargo tanks 130 are eachdesigned to retain in capacity 95% liquid gas, at approximately 45 F.,atmospheric pressure.

Water tight bulkheads 118 join the deck, second barrier, inner bottom,and separates respective cargo tanks as shown in FIGURE 1.

Individual tank foundation assembly of FIGURE 3 will now be described.It will be appreciated that each tank is provided with its individualsupporting foundation assembly 150, similarly arranged as in FIGURE 3.These assemblies are rigid with ship structure permitting relativemovement of the supported tank but fixing the latter at its center. Thetanks 130 each have abutment members 136 hereinafter described,foundation blocks on the inner bottom and at the sides thereof, alongitudinal tank block, a corresponding transverse tank block, notshown, and longitudinal stability projection block atop the tank. Theseelements comprise bearing and stability members for the tank.

Support for respective tanks 130 includes, in the foundation 150, thelongitudinally disposed keelson member 152 (FIGURES 3 and 4) having achannel 154 .supporting the tank bearing slides 156 between Micartabearing blocks 158. These blocks are located coextensively with channel154 beneath the slides and at both sides thereof in the channel. Theblocks comprise a phenolic laminate made by impregnating sheets offabric with resin and combining them under heat and pressure. The slides156 are secured by weldment to the longitudinal center of each cargotank as shown in FIGURES 2 and 4. These slides are preferably equal inlength to keelson member 152.

The entire foundation 150 is best shown in FIGURE 3, wherein thefoundation members 152 and 152'; intersect and rest upon the innerbottom 114 of the ship, foundation members and hull bottom beingpartially covered by the fixed ballast 116. The tank bearing surfaces ofthe foundation members 152 and 152 are parallel to the dihedrally shapedtank bottom. As the center of shrinkage of tanks 130 is at the bottomcenter thereof, the tank bottom is rigidly secured by weldment to theintersection of 152 and 152' keelson by fastening or bolting. From thecenter outwardly, fore and aft, however, the tank bearing slides andkeelson member are in longitudinal sliding relation as shown in FIGURES4 and 5. The tank footings or slides 156 contain multiple elongatedkeyways 160 accommodating anchor bolts 162 for movement of the slides orfootings relative to the corresponding foundation assemblies and tankblocks. The longitudinal and transverse supporting member beams 152 and152 are likewise apertured to hold the anchor bolts 1 62 relativelyfixed with respect to foundation and ship structure. Washer 164 isnon-conductive, permitting tight engagement of the tank in expansion andcontraction relation to foundation. Apertures 160 for these 'footingsare of increasing diameter from inboard to outboard, that is, from thecenterline of the ship to its sides.

This arrangement permits unrestricted tank expansion and contractionlongitudinally along the keel, transversely abeam and universallyotherwise. All bearing surfaces of the foundation are preferablygraphite lubricated. Referring to FIGURES 6 and 7 the expansion andcontraction of the tank is accommodated universally by havingcorresponding footing and stabilizer projections apertured circularly.(See FIGURE 8.) For instance, the stabilizer has apertures of greaterdiameter than does the corresponding bearing block 174 and fixed guide172. Both block and guide are fixed, having aligned apertures ofdiameter equivalent to that of the bolts whereas the movable stabilizerapertures permit universal and vertical movement as shown (FIGURE 6).Outboard of the keelson member the foundation assembly includes aplurality of aligned supports 153 each having corresponding bearingblocks 155 similarly apertured to anchor the bolts 162 vertically. Theadjacent tank slides 157 define enlarged apertures 159 permittinguniversal expansioncontraction movement of the tank at its extremitiesrelative to the fixed foundation assembly. See FIGURES 7 and 8.

To retain the tank in position, the assemblies include collision chocksforward and abeam of each tank, opposite corresponding tank abutmentmember 136. The

abutment members carry a maple wood chock; chocks and correspondingabutment members being appropriately spaced on three sides of each tankin staggered relation to each other. The forward chocks are mounteduptLn the bulkhead which is adjacent to the front of each tau The cargotanks per se are designed to withstand a 5 p.s.i.g. pressure plus thegravity head of the liquefied hydrocarbon gas, where the specificgravity is approximately 0.585 at -45 F. Steel used in the tanks ispreferably ASTM A-203 grade D or E firebox to meet ASTM-A300, Class 2with longitudinal charpy test to 75, the same steel being used for thelongitudinal wing bulkhead plating and suitable stiffeners thereof, aswell as the transverse bulkheads inboard of longitudinal bulkheads. Theinner bottom plating under the concrete ballast is of the same steel.

Deep-well pumps and hatches serve each of the cells 140 and 140' oftanks 136. Quite aside from providing personnel access to the tankinterior, the hatches 200 include vapor suction liquid level, alarmfloat, vent and fill openings as well as a liquid return opening. Thehatches 260 being located between transverse main deck girder 120 areattached to the deck by flexible water tight connection 220 made ofneoprene or the like. The connection 220 is retained between tophardwood rings and a suitable hardwood projection. The entire hatch andtank is thus universally movable irrespective of the deck, there beingno rigid connection between tank and the deck opening which surroundsthe hatch. The access hatch does not, of course, give access to thehold, but suitable hatches are provided between each tank, adjacent tothe watertight transverse bulkheads.

Deepwell pump 3% is shown in FIGURE 2, the same including similar meansfor flexibly retaining the assembly in watertight connection with themain deck. The pump shown includes a flexible connection 320, spacedinwardly from its circular water shield. From the drawing it will benoted that each pump per se is fixed to the top only of the tank cell,requiring no rigidity or attachement to the deck other than by seal32!). A circular guide 322 fits about the bottom of the pump tostabilize it against excessive swinging upon pitch and roll of the ship.This pump is preferably insulated up to its motor mount above the planeof the main deck. Insulation of the type used on the tanks is used forthis purpose. I

From the foregoing it will be apparent that the particular carrierconstruction could be modified in detail without departing from thespirit of the invention.

Accordingly, the scope of invention is determined by the appendedclaims.

We claim:

1. In bulk fluid carrier construction wherein the temperature of thecargo may vary from the ambient temperature of the carrier, the carrierhaving a hull, the combination with said carrier of (1) plural alignedholds within the hull, each said hold including (2) one tank whichextends substantially fully abeam the carrier and is spaced on all sidesfrom said hold (3) means fixed to the floor of the hold anchoring saidtank including (a) vertically aligned tank slide and (b) foundationassemblies in longitudinal and transverse coextension of the bottom ofthe tank, the assemblies each being fixed respectively to tank andfloor, raising the tank above the floor,

() a plurality of pins extending through respective foundation and slidemembers (d) both said foundation and slide members having alignedpin-engaging apertures (e) the apertures of the slides being of greaterdimension than the apertures of the corresponding foundations, wherebycontrolled expanding and contracting movements of tank relative tofoundation may occur upon cargo temperature variation.

2. The combination according to claim 1 including:

(4) anti-friction means interposed between respective foundation andslide members an in coextension thereof, I

(a) each said anti-friction means being apertured as the foundationmember, permitting movement to the slide in varying relation of saidslide to the anti-friction means and foundation member.

3. The combination according to claim 1 in which the tank carriesexterior insulation which is substantially less in thickness than thespace defined by hold and tank exterior.

4. The combination of claim 1 in which the tank bottom forms a dihedral,the center line of which is aligned with the keelson of the carrier,

and in which corresponding tank slide and foundation assembliescomprise:

(a) at least one assembly which is disposed along the center line and incoextension of the tank, (b) at least one other assembly which is intransverse coextension of the tank, the respective assembliesintersecting at the bottom center of the tank.

5. The combination according to claim 4 in which the tank carriesexterior insulation which is substanatially less in thickness than thespace defined by tank exterior and hold.

6. In bulk fluid carrier construction wherein the temperature of thecargo fluid may vary from the ambient temperature of the carrier, theimprovement comprising:

(1) an outer hull and an (2) inner hull spaced from the outer hull, saidinner hull defining (3) at least one hold (4) a tank confined within thehold and resting in spaced relation to the inner hull,

(a) the bottom of said tank defining a dihedral contour, the center lineof which is aligned with the ships keel;

(5) subjacent means of dihedral conformation anchoring the tank inexpansion-contraction, wedging re lation to the bottom of the holdincluding (a) tank slides fixed to the bottom of said tank inlongitudinal and transverse coextension of same,

(i) at least one longitudinal slide being fixed adjacent the apex of thedihedral bottom and (ii) at least one transverse slide intersecting thesaid first longitudinal slide in transverse coextension of the tank;

(6) corresponding tank foundation assemblies fixed to the floor of theinner hull, raising the tank above same;

(a) said foundation assemblies and slides defining corresponding pluralapertures (7) a plurality of projections extending into slide andfoundation apertures,

(12) the apertures of most slides being of greater dimension than theouter dimension of corresponding projections, uniting the respectiveslide and foundation assemblies in limited moving relation. 4

7. The combination according to claim 6, the tank and foundationassemblies further comprising:

supplemental tank slide and foundation assemblies disposed intermediatethe ends and sides of the tank (1) each assembly including complementalaligned apertures (2) and freely movable pins seated within theapertures all such slide apertures being of greater area than theapertures of the corresponding foundation member.

8. The combination of claim 6 in which the respective slide aperturesare of progressively greater lateral dimension from the centeroutwardly.

9. The combination according to claim 6 in which the tank carriesexterior insulation which is substantially less in thickness than thespace defined by tank exterior and hold.

References Cited in the file of this patent UNITED STATES PATENTS 97,787Marshall Dec. 14, 1869 1,986,132 Bigelow Jan. 1, 1935 2,030,881 KnightFeb. 18, 1936 2,241,822 Marsh May 13, 1941 2,520,883 Kornemann Aug. 29,1950 2,600,015 McLaughlin June 10, 1952 2,746,578 Bromeley May 22, 19562,896,416 Henry July 28, 1959 2,905,352 Henry Sept. 22, 1959 2,920,850Campbell Jan. 12, 1960 2,954,003 Farrell Sept, 27, 1960 FOREIGN PATENTS667,215 Great Britain Feb. 27, 1952 1,174,820 France Nov. 10, 1958220,768 Australia Mar. 13, 1959 813,621 Great Britain May 21, 19591,206,930 France Aug. 31, 1959

